Insights into reproductive dynamics and feeding biology of Sphyraena putnamae Jordan and Seale, 1905 exploited in the Indian EEZ

stock dynamics of Sphyraena putnamae

Abstract

The sawtooth barracuda Sphyraena putnamae, widely distributed in the Indo-Pacific region, is
one of the commercially important barracuda species exploited by trawls in the Indian EEZ.
The present study examined 2,135 S. putnamae collected during 2014-2020 from different
fish landing centres along the Indian coast, to elucidate their reproductive and feeding
behaviour. The fork length of sampled females and males varied from 12.5 to 130.9 cm and
16.5 to 90.0 cm respectively. Negative allometric growth was observed with a significant
difference (p<0.05) between the sexes. The observed sex ratio (Female:Male) was 1.23:1,
indicating the dominance of females. Size at sexual maturity for females and males were
estimated at 55.3 and 45.4 cm fork length respectively. The higher proportion of spawning
capable individuals and higher gonadosomatic index (GSI) values in females observed
during March to May and November-December revealed the bimodal and protracted
spawning nature of this species. Absolute fecundity increased with fork length and weight
and varied from 70,080 to 10,18,068 oocytes with an average of 3,16,568 oocytes. The
stomach vacuity index of females and males was 49.09 and 47.92% respectively. Fifty-nine
prey items were identified in the diet, with a predominance of fishes confirming S. putnamae
has a piscivorous feeding behaviour.

Keywords:
Management, Protracted spawners, Piscivore,
Sawtooth barracuda, Sex ratio